A Simple Hybrid Approach for the Synthesis of Heat Exchanger Networks Involving Internal Utility Exchangers

H. Soltani and Z. Pirzadeh

Abstract
This study aims to present a simple hybrid approach for synthesizing heat exchanger networks (HENs). The synthesis of HEN structures employs a genetic algorithm based on a modified node representation, closely resembling the stage-wise superstructure model. This modified representation allows for addressing the internal utility exchangers throughout the entire network. Despite the nonlinear nature of the model governing the continuous variables of each structure, a relatively simple linear formulation is developed to handle these variables. This novel formulation comprises a linear programming model for maximum energy recovery, a linear correction procedure (COP), and two search loops. The COP focuses on determining the optimal values of exchangers’ heat loads and stream split ratios to reach the minimum total annual cost of the network. The study investigates four extensively studied medium- to large-scale networks from the literature. Despite the simplicity of the proposed approach, a comparison of results demonstrates its potential effectiveness.

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Keywords
heat exchanger networks (HENs), internal utility exchangers, total annual cost (TAC), genetic algorithm (GA), linear programming (LP), correction procedure (COP)